Preparation of visible-light-responsive titanium oxide photocatalysts by plasma treatment

The reduction of titanium dioxide (TiO2) by the hydrogen plasma treatment c reates a new absorption band in the visible light region and is expected to create photocatalytic activity in this region. Anatase TiO2 powder, which has photocatalytic activity in the ultraviolet (LTV) region, was treated us ing microwave and radio-frequency (RF) plasmas. The TiO2 was reduced thus h aving an oxygen deficiency. The RF-plasma-treated TiO2 absorbed visible lig ht between 400 and 600 nm and showed a high activity in this region, as mea sured by the oxidative removal of nitric oxide from the gas phase. The plas ma-treated TiO2, which can be easily produced on a large scale, is expected to have a higher efficiency in utilizing solar energy than the raw materia l.